(1) Field of the Invention
This invention relates to sound wave projectors and more particularly, to a sound wave projector which repeatedly generates low frequency sound waves in a fluid medium such as utilized in Sound Navigation and Ranging (SONAR).
(2) Description of the Prior Art
Sound navigation and ranging (sonar) has long been utilized by underwater vessels for both navigation and detection.
Sonar utilizes sound waves which are propagated through the water and reflected back by the object(s) of interest which the sound waves strike. Sonar systems are most efficient when they rely on the generation of low frequency (less than 1,000 hertz) sound waves.
In the past, repeatedly generating low frequency sound waves in a fluid medium has proved difficult and expensive, requiring large sound projector mechanisms which are costly and include many moving parts to repair and replace. An example of such prior art systems include mechanical pistons which move water within a baffle. These devices tend to be very large in order to generate the requisite low frequency sound waves.
Additional prior art systems include piezoelectric or electromechanical transducers which vibrate in order to generate sound waves. These devices are also unreliable and do not effectively or efficiently produce the necessary low frequency sound waves.
Accordingly, what is required is an acoustical, sound wave projector which is nominally sized for repeatedly producing low frequency sound waves in a coupled fluid medium.